1. Field of the Invention
The present invention relates to a downhole drill system and de-coupling assembly utilized primarily in a heavy duty industrial setting so as to drive a hole into various types of solid, underlying terrain, the de-coupling assembly being structured to facilitate removal and interchanging of a drill head from the drill system after an extended period of use, which normally results in a severe tightening of the drill head onto a primary drive shaft, without requiring the use of substantially high strength, heavy duty machinery in order to achieve the rapid and effective disengagement of the drill head during continuing use of the downhole drill system itself.
2. Description of the Related Art
Downhole drill systems are a common type of heavy duty machinery used in a variety of industrial settings. In particular, the downhole drill systems are typically structured to drive generally straight, vertical holes into a solid underlying terrain, such as solid rock or stone. The downhole drill system typically operates with a drive shaft and a drill head coupled at a distal end thereof, typically by a threaded connection. In use, the drive shaft is repeatedly driven downwardly into impacting engagement with the underlying terrain such that the drill head effectively drives a hole into the terrain. Naturally, the dimensions of the drive shaft and the drill head dictate the size of the hole and can vary greatly depending upon the ultimately desired dimensions of the hole to be made. Also, because in many instances variations in the size of the hole is desired, such as an increase from a smaller diameter hole to a larger diameter hole in particularly hard terrain, and because of the expense of the heavy duty equipment, it is often desirable to achieve a certain degree of interchangeability of the drill head dimensions, while utilizing the same drive shaft.
Unfortunately, a primary difficulty associated with the use of downhole drill systems relates to that necessary interchanging of the drill head, both during and after use of the system. For example, drill heads may become dirty, or broken, or may require interchanging due to dimensional modifications, and therefore must be removed from the drive shaft. Because, however, of the substantial impacts to which the drill system is subjected, the drill head normally becomes increasingly tightened and secured to the drive shaft as prolonged use continues. As a result, when interchanging of the drill head is required and de-coupling by unthreading must be effectuated, substantial problems can arise if the drill head is on too tight.
Despite the need to achieve effective de-coupling, presently in the art, no system has been developed which achieves a cost effective, rapid and/or truly functional decoupling of the drill head. Specifically, the presently available techniques utilize substantially heavy equipment to gradually unthread the drill head from the drive shaft by using pure force to unthread the drill head. Because of the severe tightened engagement that results from the repeated impacts by the drill system, however, even using the heavy duty de-coupling machinery the entire de-coupling procedure can be substantially costly, difficult and time consuming. As a result, users of downhole drill systems are typically required to utilize a plurality of drive shafts, such that when interchanging of a drill head is required, normal operation with a second drive shaft can continue while the drill head is being removed over an extended period of time.
Accordingly, based on the proceeding it would be substantially beneficial to provide a downhole drill system and drill head de-coupling assembly which does not hinder the normal effective operation of the downhole drill system, but which effectively permits the removal of the drill head from the primary drive shaft after it has been used for an extended period of time. Such a de-coupling assembly should be substantially cost effective and convenient to utilize in virtually every downhole drill situation, and it should be resistant to the natural tendency of the drill head to become further tightened on the drive shaft. Indeed, such a decoupling assembly would save substantial time, effort and money by permitting rapid and effective removal of drill heads from the drive shaft, and thereby eliminate the requirement for various drive shafts at each particular job site, and minimizing the down time that may normally be associated with drill head interchanging. Moreover, an improved system should not require extended manipulation by high strength un-screwing equipment.